The effect of Al content on the Zener relaxation peak in annealed Fe-Al alloys has been investigated using a computer-controlled automatic inverted torsion pendulum through free-decay and forced vibration method. It has been shown that alloys with medium Al contents show strong relaxation while lower or higher Al content leads to relatively weak Zener relaxation peak. The relaxation in Fe-Al alloys originates from the next-nearest-neighbor atom-pairs and their interaction instead of the nearest-neighbor atom-pairs. The latter may not produce the Zener relaxation because of the ordered-structure formed, which suppresses Zener relaxation.